/*
 *    Copyright (c) 2018-2023 AsyncHttpClient Project. All rights reserved.
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *        http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 */
package org.asynchttpclient.request.body.multipart.part;

import io.netty.buffer.ByteBuf;
import org.asynchttpclient.netty.request.body.BodyChunkedInput;
import org.asynchttpclient.request.body.multipart.InputStreamPart;

import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;
import java.nio.channels.Channels;
import java.nio.channels.ReadableByteChannel;
import java.nio.channels.WritableByteChannel;

import static org.asynchttpclient.util.MiscUtils.closeSilently;

public class InputStreamMultipartPart extends FileLikeMultipartPart<InputStreamPart> {

    private long position;
    private ByteBuffer buffer;
    private ReadableByteChannel channel;

    public InputStreamMultipartPart(InputStreamPart part, byte[] boundary) {
        super(part, boundary);
    }

    private ByteBuffer getBuffer() {
        if (buffer == null) {
            buffer = ByteBuffer.allocateDirect(BodyChunkedInput.DEFAULT_CHUNK_SIZE);
        }
        return buffer;
    }

    private ReadableByteChannel getChannel() {
        if (channel == null) {
            channel = Channels.newChannel(part.getInputStream());
        }
        return channel;
    }

    @Override
    protected long getContentLength() {
        return part.getContentLength();
    }

    @Override
    protected long transferContentTo(ByteBuf target) throws IOException {
        InputStream inputStream = part.getInputStream();
        int transferred = target.writeBytes(inputStream, target.writableBytes());
        if (transferred > 0) {
            position += transferred;
        }
        if (position == getContentLength() || transferred < 0) {
            state = MultipartState.POST_CONTENT;
            inputStream.close();
        }
        return transferred;
    }

    @Override
    protected long transferContentTo(WritableByteChannel target) throws IOException {
        ReadableByteChannel channel = getChannel();
        ByteBuffer buffer = getBuffer();

        int transferred = 0;
        int read = channel.read(buffer);

        if (read > 0) {
            buffer.flip();
            while (buffer.hasRemaining()) {
                transferred += target.write(buffer);
            }
            buffer.compact();
            position += transferred;
        }
        if (position == getContentLength() || read < 0) {
            state = MultipartState.POST_CONTENT;
            if (channel.isOpen()) {
                channel.close();
            }
        }

        return transferred;
    }

    @Override
    public void close() {
        super.close();
        closeSilently(part.getInputStream());
        closeSilently(channel);
    }
}
